Renowned retired biologist Adrien Bailly is murdered. His body is dumped at the Louis Pasteur Museum in Arbois. It turns out the man died after being injected with the rabies virus. Gendarmerie Captain Hugo Villermoz and the recently assigned prosecutor Julie Dorleac must determine who might have wanted the scientist dead. Villermoz soon concludes that the prosecutor knows a great deal about him. It also turns out that the investigation into Adrien Bailly's death wasn't the only reason she came to Arbois.